Molly MacInnes

I use electrochemistry to study and design materials and interfaces. I am currently exploring two projects, both motivated by the broad goal of a cleaner, healthier Earth.

The first project involves understanding heavy metal ion interactions with oxide surfaces. Understanding these interactions is crucial for understanding both the fate of these heavy metal pollutants in the environment and how to better process waste streams containing these metals. Using conductive oxides or ultra-thin layers of non-conductive oxides on conductive materials as electrodes, we can use electrochemistry to gain thermodynamic, kinetic, and mechanistic information about the interactions of redox-active metal ions with these surfaces. We are most interested in the f-elements, i.e. the bottom two rows of the periodic table that we never talk about in classes because little is understood about these elements, but they are becoming increasingly industrially relevant.

The second project looks into ways to purify main group elements in environmentally friendly ways. Main group elements, especially silicon and germanium, are incredibly important in the electronics industry. They are critical components in solar cells and computer chips, among other applications. These elements are very abundant but exist mostly as oxides and sulfides (SiO2, GeO2, and GeS2). The current industrial methods for purifying and reducing these compounds to their elemental states involve temperatures above 2000°C and reactions with coal – hence very high carbon emissions. Recently it has been shown that SiO2 and GeO2 can be reduced to Si and Ge electrochemically using molten salts as the solvent (~ 800°C). This project explores the extent that this method is applicable. Can it be used on other main group elements? How does it depend on temperature and molten salt identity? Can we tune it to make it as energy efficient as possible? Air-free techniques (glovebox and Schlenk line work) will be crucial in this project as will electrochemistry and materials characterization methods.